Automatic circuit breaker



Oct. 6, 1942. J. H. HELLAND 2,298,053

AUTOMATIC CIRCUIT BREAKER Filed Jan. 25, 1940 2 Sheets-Sheet l 2',ATTORNEY-SE;

Oct. 6, 1942. .1. H. HELLAND 2,298,053

AUTOMATIC CIRCUIT BREAKER Filed Jan. 25, 1940 2 Sheets-Sheet 2 r 4/ 3/so I 3g i353 3/ y 42 44 29! 4.5 1 i?" 2 Z8 ,9 2 T z 46 g x 6 37 g 2 55 140 4/ I I I l 3/ 33 I I l I l i H 30 42 44 1 I w 45 24 2e A /9 I U l I57 y g I a7 49 T JHfleZZaraZ -/z I INVENTOR. J"

47 ATTORNEYS.

Patented Oct. 6, 1942 AUTOMATIC CIRCUIT BREAKER John Hilmar Helland,Newark, Ohio, assignor of one-third to William M. Pearson, Newark,

Ohio

Application January 25, 1940, Serial No. 315,608

Claims.

This invention relates to an automatically controlled circuit breaker,designed for use in the usual fuse plug socket of an electric line, theprimary object of the invention being to provide means for breaking thecircuit in which the device is located, when a short or overload occursin the circuit, thereby protecting the circuit and appliances connectedtherein.

An important object of the invention is to provide a device of thischaracter which maybe readily reset after it has operated to break thecircuit, and after the defective line or appliance has been repaired,thereby eliminating the necessity of installing a new circuit breaker inthecircuit.

Another important object of the invention is' to provide a device ofthis character including a stationary contact and a movable contact,,the

movable contact being positioned and constructed in such a way that itwill snap into engagement c with the stationary contact, completing thecircuit, thereby eliminating any possibilit of arcing, when the movablecontact member engages the stationary contact member.

With the foregoing and other objects in view,

which will appear as the description proceeds, the invention resides inthe combination and arrangement of 'parts and in the details ofconstruction hereinafter described and claimed, it being understood thatchanges in the precise embodiment of the invention herein described,

may be made within the scope of what is claimed,

without departing from the spirit of the invention.

Referring to the drawings:

Figure 1 is a longitudinal sectional view through a device constructedin accordance with the invention.

Figure 2 is a sectional view taken on line 2-2 of Figure 1.

Figure 3 is a sectional view taken on line 3-3 of Figure 1.

Figure 4 is a sectional view taken on line 4-4 tion of the circuitbreaker which is formed'with a reduced end portion 6 formed with threadsto accommodate the screw sleeve 1 that has an inwardly extended annularflange 8 formed at the lower end thereof. This annular flange provides asupport for the insulating member 9, through which the contact wire 10extends, the wire l0 being connected with the solenoid coil 1 I mountedwithin the reduced end portion of the shell or body portion 5.

The coil II is mounted on the spool-like sup port 12, and is secured inposition by means of the screw l3' which is shown as extended throughthe plate l4 that closes the lower end of the reduced portion 6.

Mounted within the support I2, is a coiled spring indicated at l5 whichis of the contractile type, the lower end of the spring being secured tothe support l2, at I6. The upper end of the spring [5 is secured to themovable contact support i! so that the normal tendency of the spring i5will be to draw the movable contact support l7 downwardly, or towardsthe coil I I.

Contact ring indicated at I8 is secured to the movable contact support17, as clearly shown by Figure 1 of the drawings.

As clearly shown by Figure 1 of the drawings, the bod portion isprovided with a plurality of bores disposed longitudinally thereof, thebores being of diameters to accommodate the coiled springs 19, whichsprings are of the expansible type. These springs are arranged inpredetermined spaced relation with respect to each other, in a circularline.

The movable contact support I! is formed with a depending annular flange2i! inside of which the armature 2| moves. The armature 2| is mounted onthe lower end of the rod 22, which is formed with a lower taperedsection 49. The upper end of the rod 22 is threaded, and extends intothe threaded opening of the disk 41. Mounted within the shell or bodyportion 5, is a disk- 24 that supports the split tube 25, the tube 25being provided with slots extending inwardly from the lower end thereof,providing a plurality of fingers 26. heads 21 that contact with theinner surface of the depending annular flange 29, under normalconditions. The disk 24 is of a diameter to rest on the coiled springsi9 to the end that under normal conditions, the action of the springs 19will be to urge the disk 24 upwardly. A disk of mica or similarinsulating material is indicated at 28, and insulates the disk 24 fromthe springs IS.

The split tube 25 is of a diameter appreciably These fingers areprovided with larger than the diameter of the rod 22, providing ahousing for the coiled spring 29 which normally acts to urge the disk 41upwardly.

Pins indicated by the reference character 30 extend upwardly from thedisk 24 and are adapted to be engaged by the cams 3| depending from thecap 32. These cams 3| are provided with straight end portions 33, sothat when the cap is rotated to cause the cams to move the pins, thepins will snap from the cams at the straight ends thereof, for purposesto be hereinafter more fully described.

The disk 24 is also provided with an upstanding flange 34 to which thedisk 35 is connected, the disk 35 providing the cover for the thermalelement. The disk 23 is disposed between the cover disk 35 and thermalelement 36, the disk 23 being shown as resting on the thermal element atall times. The thermal element embodies disks connected at their edgesand formed with annular corrugations, and constructed of bimetallic orspecial alloy, thermo-magnetic material, which will bulge when the diskexpands under heat, due to an abnormal condition in the circuit, withthe result that the armature is drawn through the fingers, releasing thefingers 26 to the action of the coiled spring I9, which forces themovable contact support I! and contact mounted thereon, away from thestationary contact 31, breaking the circuit.

The contact member with which the contact l8 cooperates in completing acircuit, is indicated by the reference character 31, and is in the formof segmental contacts against which the contact l8 engages. the circuitbetween the solenoid coil II and stationary contact 37, the returncircuit being made through the wire 39 that connects with the contact 37at the opposite side thereof, the wire 39 being in circuit with thescrew sleeve 1.

A stem indicated at all extends from the button 4| through the coverdisk 35 and connects with the disk 23 that rests on the thermal unit 36.

Carried by the cap 32, is a ring 42 which is formed with a groove in itsperiphery, the groove accommodating the spring member 43 which is in theform of a split ring constructed to expand beyond the periphery of thering 42 so that portions thereof will extend into the groove 44 formedin the shell or body portion 5, near the upper end thereof. This springmember allows the cap to rotate, but at the same time prevents the capfrom moving longitudinally of the body portion.

Ring member 42 is prevented from rotating within the housing, by thelugs 45 that extend from the periphery thereof, and are seated inrecesses formed in the inner surface of the shell or body portion 5,

It might be further stated that the stationary contacts 31 are preventedfrom rotary movement, by the lugs 46 that extend from the peripherythereof, and lie in recesses formed in the inner surface of the bodyportion 5.

The operation of the automatically controlled switch or circuit breakeris as follows: When the device is positioned in a. fuse plug socket, themovable contact member is in the position shown by Figure 1 of thedrawings. The cap 32 is now rotated in a clockwise direction resultingin the cams 3| directing a downward movement of the pins 3!], disk 24and split tube 25. Since the disk 47 supports the rod 22 and the coiledspring 29 is positioned between the disk 41 and heads 21 A wireindicated at 38 establishes of the fingers 26, it will be seen thatdownward pressure moves the rod 22 downwardly until the sleeve and rod22 are in positions as shown by Figure 6 of the drawings. The heads 21are now in expanded position below flange 20 due to the fact thatdownward movement of the disk 24 moves the free ends of the fingers overthe tapered portion 49 of the armature 2|. Upon further rotary movementof the cap 32, the cams move so that the pins 30 snap over the straightend por tions 33 thereof. With this movement, the mov-' able contactsupport i together with the contact ring l8, are moved upwardly sincethe contact support l1 has become connected with the split tube 25,whereupon, the contact ring l8 engaging the stationary contact segment31, complete a circuit through the device.

Assuming that a short occurs in the circuit, the coil II will becomeenergized resulting in the armature 2| being drawn downwardly. It willof course be understood that when the device is in its set position, thespring IE will be placed under tension. As the armature 2| moves awayfrom the fingers 26, the fingers contract due to the resiliency thereof,leaving the movable contact support whereupon the coiled spring l5 snapsthe movable contact ring l8 downwardly away from the contact member 31,breaking the circuit.

When the device is in a set position, and an overload occurs in thcircuit, the coil II will become heated, causing the thermal element toexpand. As the thermal element expands, the disk 41 is forced downwardlymoving the rod 22 to a position where the tapered portion thereofdisengages the fingers. With this movement, the coiled spring l5contracts to move the movable contact ring I8 out of engagement with thestationary contact segment 31, again breaking the circuit.

It might be further stated that when it is desired to break the circuit,the button 4| is manually depressed, and when the device is to be reset,the cap 32 is rotated in a clockwise direction, as described.

From the foregoing it'will be seen that due to the construction shownand described, the device may be readily and easily set for operation,after the line or circuit has been repaired, without the necessity ofproviding a new circuit breaker.

What is claimed is:

1. An automatically controlled circuit breaker comprising a body portionadapted to be screwed into a fuse plug socket of an electric circuit, astationary contact member within the body portion, a movable contactmember within the body portion and adapted to complete a, circuit withthe stationary contact member, a solenoid in the circuit with thecontact members and mounted within the body portion, said solenoidincluding an armature embodying a stem formed with a cam surface, amovable member within the body portion, spring fingers carried by themovable member and normally engaging the cam surface, said fingersadapted to expand by movement of the fingers over the cam surface of thearmature stem of the solenoid, connecting the movable member and movablecontact member, means for moving the movable member whereby the movablecontact member is moved into engagement with the stationary contactmember, completing a circuit, and said solenoid adapted to disengage thefingers releasing the fingers when an abnormal condition occurs in thecircuit, and means for operating the movable contact member to disengagethe stationary contact member, breaking the circuit.

2. An automatically controlled circuit breaker comprising a body portionadapted to be secured in a fuse plug socket of an electric circuit, astationary contact member within the body portion, a movable contactmember within the body portion, a support for the movable contactmember, said support including an annular flange, a movable membermounted within the body portion and including spring fingers, adapted toextend to a position adjacent to the annular flange of the movablecontact member, a solenoid within the circuit and including an armaturestem having a cam surface formed thereon movabl between the springfingers and adapted to expand the spring fingers into frictional contactwith the flange of the movable contact member support, means for movingthe movable member and movable contact member whereby the movablecontact member engages the stationary contact member completing thecircuit, said solenoid adapted to be energized when an abnormalcondition arises in the circuit, whereby the cam surface moves away fromthe spring fingers, releasing the movable contact member, and springmeans for actuating the movable contact member to break the circuit.

3. An automatically controlled circuit breaker comprising a body portionadapted to be screwed into a fuse plug of an electric circuit, astationary contact member and a movable contact member mounted withinthe body portion, a movable member above the stationary contact member,spring fingers carried by the movable member, a solenoid having atapered armature stem mounted within the body portion the taperedportion of said armature stem adapted to extend between the springfingers expanding the fingers into engagement with the movable contactmemher and connecting the movable member and movable contact member,said armature stem adapted to move between said spring fingers in onedirection, releasing the fingers, when the solenoid is energized due toan abnormal condition in the circuit, and means for moving the movablecontact member out of engagement with the stationary contact memberbreaking the circuit when the movable contact member is released by saidfingers.

4. In a device of the character described, a body portion adapted to bescrewed into a fuse plug of an electric circuit, a stationary contactmember and a movable contact member mounted within the body portion, alatch adapted to normally hold the contacts together, said latchcomprising a tube split longitudinally from one end, providing springfingers, a solenoid in the body portion and embodying a tapered armaturestem adapted to move between the spring fingers urging said springfingers laterally into frictional engagement with the movable contactmember connecting said movable member and said movable contact member,yieldable means adapted to move said movable contact member to aposition closing a circuit between the movable contact member andstationary contact member, and said tapered armature stem adapted tomove releasing said fingers and freeing said movable contact member whenthe solenoid becomes energized, and a spring adapted to move the movablecontact member away from the stationary contact member breaking thecircuit.

5. An automatically controlled circuit breaker comprising a body portionadapted to be screwed into a fuse plug socket, a stationary contactmember including an annular flange, mounted within the body portion, amovable contact member mounted within the body portion and adapted toengage the stationary contact member completing an electrical circuit, amovable member extending through the movable contact member, saidmovable member embodying a tube split longitudinally providing aplurality of spring fingers, a solenoid within the body portion and incircuit with the contact members, a tapered stem forming a part of thesolenoid and adapted to extend into the split sleeve expanding saidfingers into frictional engagement with the annular flange holding thesleeve and movable contact together in a set position, said solenoidadapted to Withdraw the said tapered stem, releasing the fingers, and aspring adapted to move the movable contact member away from saidstationary contact member breaking the circuit.

JOHN HILMAR HELLAND.

